Circuit breaker operating mechanism



Nov. 2, 1954 J. K. HODNE'ITE ETAL 2,693,515

CIRCUIT BREAKER OPERATING MECHANISM Original Filed JulyA 5, 1947 2Sheets-Sheet l NUV- 2, 1954 J. K. HoDNETrE ETAL CIRCUIT BREAKEROPERATING MECHANISM 2 Sheeis-Sheet 2 Original Filed July 5. 1947 MUNoverload current to thermal element responsive to ambient temperaturesto .to effect yof the invention are United States Patent C 'CIRCUITBREAKER OPERATING MECHANISM John K. Hodnette, Pittsburgh, and Merrill G.Leonard,

Sharon, Pa., assignors to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Penn- Sylvania Original applicationJuly 5, 1947, Serial No. 759,272, now Patent No. 2,536,429, datedFebruary 19, 1952. Divided and this application August 8, 1951, SerialNo. 240,875

Claims. (Cl. 200--116) This invention relates to circuit breakers, andmore particularly, to operating and tripping mechanism therefor.

This application is a division of copending application Serial No.759,272, tiled July 5, 1947, by John K. Hodnette and Merrill G. Leonard,now Patent No. 2,586,429, issued February 19, 1952, and assigned to theassignee of the present invention.

One object of the invention is to provide a circuit breaker embodying animproved operating mechanism wherein the load of the main operatingspring is not imposed on the breaker latch.

Another object of the invention is to provide a circuit breakerembodyinga trip member controlled by a thermal trip element to trip the breaker.and to eiect an indication of the condition of the breaker, and anindicating trip member controlled by said thermal trip element to effectan indication of the approach of a dangerous circuit condition.

Another object of the invention is to provide a circuit breakerembodying a trip member controlled by a thermal trip element to trip thebreaker and to effect an indication of the condition of the breaker, anindicating trip member controlled by said thermal trip element to etfeetan indication of the approach of a dangerous circuit condition and meansoperatively relating the operating mechanism of the breakerand theindicating trip member to permit resetting of said indicating tripmember without disturbing the breaker contact position.

Another object of the invention is toprovide a circuit breaker embodyinga thermal trip device responsive to trip the breaker and an auxiliarycontrol the thermal trip device to trip the breaker after a relativelylong time delay when the ambient temperature is low and after arelatively short time delay when the ambient temperature is high.

Anotherobject of the invention is to provide a circuit breaker embodyingoperating ymeans and two auxiliary devices controlled by a singlebimetal element, 'one of said auxiliary devices is reset bypredetermined movement of said operating means without resetting theother of said auxiliary devices.

A further object of lthe invention is to provide a circuit breakerembodying a trip member controlled by a thermally responsive tripelement -to trip the breaker and to effect an indication and anindicating trip member controlled by said 'thermally responsive tripelement an indication, in which individual adjusting means is providedto adjust the relative positions of said trip n'xembers and saidthermally responsive element.

Another-object of the invention is to provide a circuit breakerembodying two releasable members controlled by a single bimetal element,one of said members when released effecting a signal and the other ofsaid members when released causing opening ofthe breaker, and twoadinsting means for adjusting the relative positions of said bimetalelement and said members, the signal member being adjusted by movementthereof relative to said biinetal element.

The novel features that are considered characteristic set forth invparticular in the appended claims. The invention itself. however, bothas .to structure and operation, .together with vadditional ob- Fig. 2 isa sectional view taken on line II*II of Fig. l

4and looking in the direction of the arrows,

Fig. 3 is an elevational view similar to Fig. 1 but showing the breakerin the tripped open position, and

Fig. 4 is an elevational view similar to Fig. l but showing the parts inthe reset position.

Referring to Fig. l of the drawings, the circuit breaker comprises abase 11 of insulating material on which is mounted the breakercontactstructure, a metal housing 13 secured to the base 1'1, anoperating mechanism indicated generally at 15 and a trip deviceindicated generally at 17.

The contact structure comprises a main stationary contact 19 rigidlymounted on the inner end vof a rod 21 slidably mounted in the base 11. Acoil spring 23 surrounds the rod 21 and is compressed between the baselland a connector 25 secured to the rod 21 and to the contact 19 toprovide contact pressure. A limit nut 27 is threadedly mounted on therod 21 outside the base 11. A cooperating movable contact 29 is rigidlymounted on a channel-shaped switch arm 31 pivotally mounted on a pivotpin 33 supported in a yU-shaped bracket 35. The bracket 33 is secured tothe base 11 by means of a screw 37 The contact structure also comprisesa stationary arcing contact 39 rigidly mounted on a conducting supportmember 41 secured by means of a screw 43 to the base 11, and acooperating movable arcing contact 45. The movable arcing contact 45 isrigidly mounted on a channel-shaped switch member 47 which straddles theswitch arm .31 and is pivoted on the pivot pin 33. A compression spring49 disposed between an eXtension 51 of the main switch arm 31 and theyoke portion 53 of the arcing contact switch arm 47 provides contactpressure for the arcing contacts 3945 and also maintains the arcingcontacts in closed position until after the main contacts 19-29 haveseparated on an opening operation.

The operating mechanism 15 is supported in agenerally U-shaped frame 55the Abight 57 of which is rigidly secured to the housing 13. Theoperating mechanism .comprises a releasable member or carrier 59pivotally mounted on atiixed pivot pin 61 mounted in the side members ofthe frame 55. The carrier 59 has a latch portion 63 adapted to engage alatch member 65 forming part of the trip mechanism which will be morefully described hereinafter. The carrier 59 is biased in a clockwisedirection by means of a spring 67 which surrounds a spring guide 69pivotally connected at one end by means of a pivot pin 71 to thecarrier. The spring 67 is compressed between a shoulder on the springguide 69 and a rod 73 mounted on and extending between the side membersof the frame 55. The carrier v59 lis operatively connected to the switcharm 31 by means of a toggle comprising toggle links 75 and 77 pivotallyconnected together by Va knee pivot pin 79. The toggle link V75 is ofinsulating material and is pivotally connected to the switch arm 31 bymeans of a pivot pin 81. The toggle link 77 is pivotally connected bymeans of a pivot pin 83 (Fig. 3) to the carrier 59. The pivot pin 33 isdirectly under and concentric with the pivot pin 89 (hereinafterdescribed) when the carrier 59 is in its normal latched position, asshown in Fig. 2. The pivot pin 81 projects beyond the side members ofthe switch arm 31 and through elongated slots 85 (only one being shown)in the side members of the arcing contact switch arm 47.

An actuator comprising 'a pair of spaced actuating levers 87 is providedfor operating the toggle 75-77 to manually open and lclose the contacts.The actuating levers`87 are disposed adjacent the inner sides of the-U-shaped frame 55 and each of the levers carries a ,pivot pin89 whichis seated in a slot 91 in the adjacent frame. The actuating levers 87are rigidly joined by an A integral cross member 93 and each of thelevers 87 is provided with a hook portion 95 which in the closedposition of the mechanism engages an end of` the knee pivot pin 79 tohold the toggle 75-77 in a slightly underset position to thereby holdthe switch arms 31 and 47 in the closed contact position.

A pair of overcenter springs 97 is provided to operate the levers 87 andtherethrough the toggle 75-77 in order to manually open and close thecircuit breaker. The springs 97 have one end hooked over laterallyprojecting ears 99 on the levers 87 and the other ends of the springsare hooked over an operating rod 101 extending through guide slots 103disposed in parallel alignment in the frame members 55. Securedl to `ashaft 105 for rotation therewith is a pair of operating arms 107 eachhaving its free end bifurcated to embrace the rod 101 adjacent the endsthereof. The shaft 105 1s `pivotally supported in plates 109 secured tothe outside of the housing 13 and provided with mounting feet 111whereby the circuit breaker may be mounted on a suitable support (notshown). One end or' the shaft 105 extends to the outside of the housingand has secured thereto an operating handle indicated at 113 (Fig. 2)for manually operating the shaft 105 and the arms 107.

The circuit breaker may be opened manually by rotating the handle 113and consequently the shaft 105 and arms 107 approximately 90 in acounter-clockwise direction from the position shown in Fig. l. thismovement thearms 107 cause the'rod 101 to move upwardly in the slots 103carrying therewith the ends of the springs y97 attached thereto. Whenthe rod 105 moves the line of action of the springs 107 overcenter abovethe pivot 89 of the levers 87, they bias the actuator levers 87 in aclockwise direction. Continued movement of the arms 107 and the rod 101increases the biasing force until a point is reached when the springsrotate the actuating levers 87 clockwise about the pivots 89. In theclosed and latched position of the circuit breaker, the pivot 83connecting the toggle link 77 to the releasable carrier 59 is in axialalignment with the pivot 89 of the actuating lever 87 and the knee pivotpin 79 remains in engagement with the hook 95, consequently, the togglelink 77 and the lever 87 will move as a unit yduring manual openingoperation. The clockwise movement of the actuator lever 87, therefore,causes collapse of the toggle 75-77 and opening of the contacts. Duringthe opening movement of the mechanism the switch arm 31 is rst moved ina counterclockwise or opening direction to open the main contacts 19-29while the spring 49 maintains the arcing contacts 39-45 closed untilafter the main contacts have separated. Shortly after the main contactshave separated, the pin 81 engages the outer end of the slot 85 in theswitch arm 47 and thereafter moves both switch arms 3.1-47 to the fullopen position in unison in which position the parts v are shown in Fig.4.

The contacts are closed by rotating the shaft 105 and the arms 107clockwise from the Fig. 4 position to the position in which thev appearin Fig. l. During this movement the arms 107 carry the rod 101 therewithmoving the line of action of the springs 97 overcenter below the alignedpivots 83-89, whereupon the springs 97 bias the actuating lever 87 in acounterclockwise direction, and, since the knee pin 79 of the toggle75-77 is in engagement with the hook 95, the toggle is biased to itsunderset position. Continued clockwise movement of the arms 107increases the spring bias on the actuating lever 87 and the toggle untila point is reached where the springs 97 suddenlv straighten the toggle75-77 and close the contact with a snap action.

The conguration of the slot 103 is substantially concentric with theears 99 on the actuating levers 87 so the slot controls the springs 97so as to produce as little change as possible in the length of theovercenter springs 97 until the toggle is broken, thereby reducing theenergy required to operate the breaker. As will be more fully broughtout later. the shape of the slots 103 also controls the operation of areset lever.

The circuit breaker may be tripped open automatically by operation ofthe trip device 17 in response to overload currents. The trip devicecomprises a base 115 of insulating material secured to the housing 13, acover 117 also of insulating material secured to the base 115 by meansof rivets 119 (only one being shown), a biased During ,j

switch members 31 and 47 to the open position.

lease the member 121. The bimetal element is secured at one end to ametal bracket 124 supported on insulating plate 125 mounted on the base115 and at the other end carries an insulating block 127 to which issecured a metal latch 129. A connector 131 is electrically connected tothe free end of the bimetal element and a flexible terminal conductor133 is connected to the connector. The flexible conductor 133 extends tothe left and is supported on a bracket 135 mounted on the base 115.VFlfhereafter the conductor 133 extends out through an opening in thecover 117 where it serves to connect the breaker in an electricalcircuit. The bracket 124, and hence, the iixed end of the bimetalelement is connected by means of a flexible conductor 137 to the switcharms 31` and 47, the conductor 137 extending downwardly through anopening in the base 115 where it is mechanically and electricallysecured to a connector 139, and to the switch arms 31 and 47. Theconnector 139 provides a point where a terminal strip 140 may beconnected to provide a third terminal between the bimetal and thecontrols. The main stationary contact 19 is connected by means of aexibie conductor 141 to the stationary arcing contact 39 and the circuitthrough the breaker is completed by means of a flexible terminalconductor 143 also connected to the iixed arcing contact 39 andextending out through an opening in the base 11. An auxiliary bimetalelement 145, disposed above the tripping bimetal 123 but insulatedtherefrom by a strip 147 of insulating material, is xedly mounted at itslefthand end and adapted to deflect, when heated, in the same directionas the tripping bimetal 123.

The releasable member 121 is pivotally mounted at 149 on an adjustingarm 151 which, in turn, is pivotally mounted on a pivot pin 153 which issupported in a suit- 'able opening in the base 115. The pivot 149,adjusting cam 151 and pivot pin 153 are directly behind pivot 189, asecond adjusting cam 191, and pivot pin 193, as hereinafter described.The member 121 is biased by means of a spring 155 in a clockwise ortripping direction. The spring 155 has one end hooked into an opening inthe member 121 and the other end anchored to the free end of theadjusting arms 151. Secured to the adjusting arm 151 at a point adjacentits free end is a rod 157 (Fig. 2) which extends lupwardly through anenlarged opening in the base 115 and has its upper end threaded toreceive an adjusting nut 159. A spring 161 coiled about the rod 157 andcompressed between the bottom surface of the base 115 and a washer 163biases the free end of the arm 151 downwardly. By turning the nut 159inV one direction the rod 157 may be moved upwardly rotating the arm 151in a counterclockwise direction. Turning the nut 159 in the oppositedirection permits the spring 161 to lower the rod 157 and rotate the arm151 in a clockwise direction. Since the releasable member 121 ispivotally supported at 149 on the arm 151, it Will be thus moved up ordown relative to the latch 129 to thereby vary the overlap of the member121 with the latch.

The latch member 65 is U-shaped and the two legs thereof are mounted ona shaft for movement therewith, the shaft 165 being mounted for rotationin openings in the side members of the frame 55. The yoke portion 167 ofthe latch member is shaped inwardly to form a latch portion 169 whichengages the latch portion 63 of the carrier 59 to normally restrain thelatter in the position shown in Fig. l.

The bimetal element 123 has its high-expansion side facing downwardly sothat, when heated a predetermined amount in response to overloadcurrents, the bimetal element 123 will deflect upwardly to disengage thelatch 129 from the releasable memberr121. When this 0ccurs, the spring155 rotates the member 121 clockwise about its pivot 149 and the lowerend 171 thereof strikes the latch member 65 a blow to disengage thelatch portion 169 thereof from the latch portion 63 of the carrier 59thereby releasing the carrier. Upon release ofthe carrier 59, the spring67 rotates the carrier in a clockwise direction about its pivot 61 tothe position 1n which it appears in Fig. 3, thus moving the u During theearly portion of this movement the knee pin 79 of the toggle 75-79 movesout of the hook portion 95 of the actuator levers 87 and shortlythereafter the end o f the spring guide 69 strikes the toggle link 77.This action Causes collapse of the toggle and rotates the toggle -link7-7 clockwiseV about its pivot 83? to efectmovement. of

the switch arms 31.--47-y tothe opemposition. The. mechanismV is shownyinf.y Fig, 3. in the tripped; open position.

During the automatic. openingT operation, the knee pivot, pin 79, aspreviously set forth, escapes from the actuating levers 87' and: beforeIthe breaker can bel reclosed it is necessary to reengage the actuatinglevers with the knee pin 79 and alsoV to reset and relatch the carrier59. Both of these operations areaccomplished by moving the rod 101upwardly iny theV sl'ots 103 from the Fig. 3 positionj to-thepositionshown in Fig; 4; This is done byrotating the shaft 105 and thearms 107 in a counterclockwise direction as far as they willV go, themovement of the rod beingy limited' byv engagement with theupper. end ofthe slot 103; During' this movement the rod 101 carries the line, ofaction: of thev springs 97 overcenter above. the pivot 89 (Fig. 3:) ofthe levers 87 whereupon the springs 97 actuate the levers in a clockwisedirectionV untily they engage the knee pin 79. Next in its upwardtravel, the rod` 101 engages a projection 173 on the carrier 59 androta-tes the: carrier; counterclockwise about its pivot, 61. Near` theend of this movement of the' carrier 59- the` latching end thereofwipes'by the latch portion 169 of theA latch member 65 which is thenrestoredclockwise: to@ latching; position by means ofV a spring 1-75,the. clockwise movement of the latch 65 being limited by engagementwithv, the frame: 55. During the counterclockwisemovement of the:carrier 59, the pivotl 83 for the toggle linkv 77 moves back slightlybeyond the normal position in which it is aligned with the pivot 89 ofthe levers 87; This movement.r thrusts the knee pin' 79 into the; hookportion` of the levers. 87', and provides a slight overthrow for` thevlatching portion 63 of theV carrier beyond latched position'.

The rod 101- in its upward travel, next engages a cam surface 1'77 inone wall of a. slot 179'in aresettingY lever 181 which is pifvotallymounted. onY the: pivot. pin 651, and in cooperationv with theslotsy103'f,.movesthis'- lever coun*- terclockwise about its: pivot. Duringthis movement, an ear'183 (-Figs; 2 and 4)- formedi at'rightA angles tolthe upper end of the resetting' lever engages the releasable trippingmember 121- and rotates it countercloekwise past its latchedlpositionvas. shown in' Fig; 4.. T he parts are now in the reset position astshowny in` Fig. 4', in readiness for acoutact closin'goperation. whichis effected in the previously describedmanner'by movement of the arms107 and the rod; 101. iny a clockwise direction to the Fig. lv positionduring whichmovement' the'l actu'- ating levers 87 acting throughv theVknee: pin` 79f straightens the; toggle 75-77 and movesV the: switch armsto their closed positions; As the rodz 101 nears. thelower.` end of itsmovement, it; engages a portion' 185' ofi the: slot 179 in theresettingl lever: 181iY and restores. this. lever: to its initialposition, asv shown.` in Fig.. l.

The circuit breaker. is designed for usey in an oil insul'atedtransformer, and it is the purpose of theauxiliary bimetal element 145lto modify the tripping time of. the current-carrying tripping bimetalelement 123' in accord ance with thetemperature ofy thev surroundingmedium. The bimetal element 1.45 is. similar to the tripping bi= metal123y and also has its high-expansion side facing downwardly, hence, whenheated, will deflect iu the same direction as the tripping birnetal 123.

lf the transformer temperature rises gradually so that the. mass ofcopper, oil insulation, etc., tend to reach their maximum' safetemperatures, the auxiliary bimetal 145, which is heated by the oiltemperature ris-e and to some extenty by conduction and convection fromthe tripping bimetalv 123', willv deect in the same direction and atapproximately the same rate as the tripping bimetal 123 whichk isheatedby both current flow and oil temperature rise, hence the bi'rnetal145 will not appreciably change the trip-time curve ofthe trippingbimetal 123. If the transformer temperature is low and heavy overloadoccurs,l the tripping bimetal 123 will be heated rapidly, whereas thetemperature of the auximiary bimetal' 145 will rise veryV little andwill,v therefore, exert a restraining force on the tripping bimetal 123.lt will be seen, therefore, that for a given value of overload current,the circuit breaker willv be tripped open after a relatively short timeAdelay when the transformer tem'- perature is high and after, arelatively long time delay when the transformer temperature is low. Byuse of the auxiliary bimetal 1'45 heavier overloads may be carried forAa short time without tripping, and@ the greater temperature'V ri'serequiredr toy trip' on such overloads;v will give. faster cooling andthereby thev time for resetting is reduced.

The trip-time curve of the trip device may be varied by substitutingbimetal elements having dilerent characteristics for the auxiliarybimetal element, by varying the space between the tripping bimetal andtheY auxiliary bimetal andby varying they thermal insulation between andaround' the bimetal elements and also by varying the characteristics ofthe tripping bimetal.

Means is providedl for indicating a'y partial overload condition whichis not of suicient magnitude to trip the breaker open but whichindicates that' the current in the circuit is approaching a dangerousoverload con-` dition or that a dangerous overload conditionv has beenapproached and then cleared itselfwithout tripping the breaker, alsotoindicate that the breaker has been' tripped open in response' to adangerous overload condition.

The indicating mechanism comprises a releasable member 187` (Figs. l and2) pivotally supported by means of a pivot pin 189- on an adjustinglever 191, The' lever 191V is pivotally mounted on the pivot pin 153which supports the lever 151l on the baseV 115 of the trip device. A-spring 195 having one end hooked inv an opensing in one arm of thereleasable member 187' and' the other end hookedin-an opening in thelever 191 biases the member 187 in a clockwise direction about its pivot189. The member 187 is normally restrained against clockwise movement byengagement with the latch 1-2-9. An adjusting rod 197 (Fig. l), similartothe rod' 157 (Fig. 2') for the lever 151,. is secured to the lever 191at a point near its free end and extends upwardly through an openinginthe base 115. The upper end of the rod 197 isthreaded to receive anadjusting nut 1'99 and" a compressionr spring 201V coiled about the rod197 is disposed between the base and a Washer 203 bearing against thelever 191. By thisy means thelever 191 can be movedup' and down aboutitsl pivoty 193 to thereby shift the pivot 189I for the member 187 andvary the amount of overlap between the member- 187- and the latchl 129;The member 187 is adjusted tobe releasedv bythe latch 129 before thebimetal' element 123 deflects far enough to release the member 121 to`trip the, breaker. Thereleasable member 187 is electrically conncted bymeans of ay flexible conductor 205 to a conductor 207 extendingtransversely throughy the'breaker and secured to the base 115- of thetrip device. The member 187 ismade of conducting material and carries astud. or contact 209V also of conductingy material which, upon releaseand. clockwise movement of the member. 187 isv adapted to. make butt.engagement with thev end of. a fixed. contact 211 to thereby' close anelec'- trical circuit and energize anv indication device (not shown)but, preferably a signal. lighty to give visual indication.

The releasable tripv member 121 is also electrically connected by meansvof. a flexible conductor 213 to the conductor 207 and carries a Contact215 which, upon release of the member. to effect tripping of thebreaker, engages the end of a fixed. contact 217Y directly behind thefixed Contact 211 and. closes an electrical circuit to energize anindicating device. The fixed contacts. 2.11 and 217 may be connectedtogether andy connected in a circuit (not shown)y to energize. a singleindicator or they may be connected in separate circuits to energizeseparate indicators.` The return circuitv (not shown) from theindicators is connected to a supply conductor 21.9 also secured to thebase 11-5 but insulated from. thel supply circuit 207. The supplyconductors 20.7 and. 219 extend outside of the housing13 (Fig. 2) to.beconnected to a supply circuit, or to be connected to. similar con'-ductors in another circuit breaker assembled adjacent the irst breakerin a manner to be more fully described ater.

As previously stated, the releasable signal member 187 is adjusted bymeans of the lever 191 and the adjusting rod 197 (Figs. l and 2) to tripand close the circuit to the indicator before the relcasable trip member121 is released to trip the breaker. Hence, if. an overload currentoccurs which. approaches adangerous valueand trips the signal member1857, but which is cleared before it releases thetri;` member 12.1, themember 187 will close its circuit and energize the indicating means.Under this circumstance, it is desirable to rcset. the membery 187without opening' or otherwise disturbing the main breaker contacts. Thisis accomplished by a partial stroke of the arms 107 and the rod 101 inopening direction which is effected by a partial opening stroke of thehandle 113 (Fig. 2). During this partial stroke, the rod 101 engages thecam portion 185 of the resetting member 181 and rotates this member in aclockwise direction from its Fig. 1 position causing an ear 221 on themember 181 to engage an arm 223 on the member 187 to rock the latter ina counterclockwise or resetting direction to its relatched position asshown in Fig. l. After the release signal member 187 is relatched, thearms 107 and the rod 101 are restored clockwise to their normalpositions and since the rod 101 was not moved far enough to carry thesprings 97 overcenter, the main contacts remain in their closedposition. If a single indicating device is utilized which is energizedby both the releasable member 121 and 187 with their contactselectrically. connected in parallel, and this indicator remainsenergized after the member 187 has been reset, it indicates that thebreaker has been tripped open and must be reset and reclosed. However,with two indicators operated independently by the member 187 and thetrip member 121, a single energized indicator would inform the attendantthat an overload had occurred but had cleared without tripping thebreaker, in which event it would only be necessary to reset the member187 without opening the breaker. If both indicators were energized theattendant would know immediately the breaker was tripped open and mustbe reset and then reclosed.

As previously stated, two or more circuit breakers may be assembled andtied together for unitary operation to control a multi-phase circuit.While only a single circuit breaker has been described, the breakers tobe assembled are identical, hence, only the means for nroviding unitaryoperation of two or more circuit breakers will be described. When two ormore breakers are assembled together, the plates 109 together with themounting feet 111 are omitted except those on the outside of the endbreakers and the breakers are secured together by means of a pluralityof bolts 225- (Figs. l and 2) passing through all of the assembledbreakers and having nuts 227 threadedly engaging the ends thereof. Thetrip shafts 165 and the latch members 65 are tied together for unitarymovement by means of a sleeve 229 (Fig. 2) which couples the shafts 165so that a tripping operation of the latch member 65 for one of thebreakers in response to an overload current occurring in the relatedphase circuit will operate the latch members for all of the breakers.The operating shaft 105 described for the single pole breaker isreplaced by a similar shaft 231 (Fig. 2) which extends through all ofthe breakers and has secured thereto for movement therewith theoperating arms 107 for each breaker. Operation of the shaft 231 willeffect manual opening and closing of the contacts of all of thebreakers, reset and relatch the mechanism and reclose the contacts ofall the breakers in the same manner as was described for the single poleunit.

The supply conductor 207 for the indicator device of each phase breakeris provided at one end with a spring clip 233 (Fig. 2) for releasablyreceiving the externally projecting end of the conductor of the adjacentphase breaker so that the supply circuit extends through all of thebreakers. The supply conductors219 are grounded to their respectivemetallic housings.

From the foregoing description, it will be apparent that there isprovided a circuit breaker embodying `a tripping mechanism controlled bya thermally responsive element for opening the breaker contacts undercertain overload current or temperature conditions and for effecting anindication of the condition of the breaker operating mechanism. There isalso provided a second trip mechanism controlled by the thermallyresponsive element for effecting an indication of the approach of adangerous overload or temperature condition of a lesser magnitude thanthat required to trip the breaker. The arrangement of the tripmechanisms being such that in the event the condition which causedoperation of the second trip mechanism disappears without having trippedthe breaker, the trip mechanism may be reset by partial operation of thebreaker operating mechanism without disturbing the position of thebreaker contacts. There is also provided independent adjusting means foradjusting the trip mechanism to vary the amount of overload currentrequired to trip the breaker'and for independently adjusting indicatingtrip mechanism to vary the amount of overload and/ or temperature riserequired to effect an indication without tripping the breaker.

Having described the invention in accordance with the patent statutes,it is to be understood that various changes and modifications may bemade in the structural details thereof without departing from some ofthe essential features of the invention.

We claim as our invention:

1. In a circuit breaker comprising a switch member and operatingmechanism for moving said switch member to open and closed circuitpositions, an auxiliary device, a plurality of members movable from anormal position to an operating position, one of said members when movedbeing operative to actuate said auxiliary device and the other memberwhen moved being operative to actuate said auxiliary device and toeffect movement of said switch member to open position, a trip devicecomprising a bimetal element normally engaging and restraining saidmovable members, said bimetal element being operable in response topredetermined abnormal conditions to effect movement of said one memberto actuate said auxiliary device and further operable to effect movementof said other member to actuate said auxiliary device and to effectmovement of said switch member to open position, and means operable bypredetermined movement of said operating mechanism to reengage said onemember with said bimetal element without moving said switch member fromthe closed position.

2. In a circuit breaker comprising a switch member and operatingmechanism for moving said switch member to open and closed circuitpositions, an auxiliary device, a plurality of members movable from anormal position to an operating position, one of said members when movedbeing operative to actuate said auxiliary device and the other memberwhen moved being operative to actuate said auxiliary device and toeffect movement of said switch member to open position, a trip devicecomprising a single bimetal element normally restraining said movablemembers and operable in response to predetermined abnormal conditions toefect movement of said one member to actuate said auxiliary device andfurther operable to effect movement of said other member to actuate saidauxiliary device and to effect movement of said switch member to openposition, and means operable by said operating mechanism to reset saidone member without moving said switch member from the closed position,separate means for movably supporting each of said members for movementrelative to said bimetal element and adjusting means for independentlyadjusting said support means to adjust said members relative to saidbimetal element to thereby vary the conditions required to effectmovement of said members.

3. In a circuit breaker comprising a switch member and operatingmechanism for moving said switch member to open and closed circuitposition, a plurality of sets of auxiliary contacts, a plurality ofmembers movable from a normal position to an operating position, one ofsaid members when moved'closing a first set of auxiliary contacts, andthe other member when moved closing a second set of auxiliary contactsand also causing automatic movement of said switch member to openposition, a trip device comprising a thermal element having latch meansthereon normally restraining said members against movement, said thermalelement being operable in response to overload currents of predeterminedmagnitude to release said one member and further operable in response tooverload currents above said predetermined magnitude to release saidother member, movable support means for said members, and meansadjustably moving said support means to independently move said membersrelative to said latch means to thereby vary the magnitude of overloadcurrents required to release said members.

4. In a circuit breaker comprising relatively movable contact means andoperating mechanism therefor, a trip member releasable to effectautomatic opening of said contact means, a trip device comprising athermal element releasably restraining said trip member and operable inresponse to overload currents of predetermined magnitude to release saidtrip member, auxiliary contact means operable to closed positions bysaid trip member upon release of said trip member, adjusting means foradjusting the position of said trip member relative to saidthermal'element, a second auxiliary contact means. a

member releasable by said thermal element in response to overloadcurrents of lesser magnitude to close said second auxiliary contactmeans, adjusting means for adjusting the position of said releasablemember relative to said thermal element, means operable bv saidoperating mechanism to reset said trip member and said releasable memberto effect opening of both auxiliary contact means, and said resettingmeans being operable by predetermined movement of said operatingmechanism to reset said releasable member and open said second auxiliarycontact means while said circuit breaker remains closed.

5. In a circuit breaker comprising a switch member and operatingmechanism for moving said switch member to open and closed positions, anauxiliary device for effecting a signal, a plurality of members movablefrom a normal position to an operating position to actuate saidauxiliary device, one of said members when moved being operative toactuate said auxiliary device, the other of said members when movedbeing operative to actuate said auxiliary device and also to effectmovement of said switch member to open position, a trip devicecomprising a tripping bimetal element connected in the circuit to beheated in response to overload currents, said bimetal element deectingwhen heated a predetermined amount to effect movement of said one memberto actuate said auxiliary device, and further deecting when heated agreater amount to effect movement of said other member to actuate saidauxiliary device and to effect movement of said switch member to openposition, and a second bimetal element disposed adjacent said trippingelement to be heated by the surrounding medium, said second bimetalelement normally opposing tripping movement of said tripping bimetal,and said second bimetal when heated deecting in the same direction asthe tripping bimetal element to permit free deflection of said trippingbimetal element.

6. In a circuit breaker having a switch member movable to open andclosed positions, operating mechanism for moving said switch member toopen and closed positions, indicating means comprising a pivotedindicating member movable from a normal position to an indicatingposition to effect an indication of a predetermined circuit condition, apivoted trip member movable to effect automatic opening movement of saidswitch member, a single bimetal element heated in response to thecurrent of the circuit and normally restraining said members, thermalbending of said bimetal element in response to overload currents ofpredetermined value causing release of said indicating member, thermalbending of said bimetal element in response to overload currents greaterthan said predetermined value causing release of said trip member toeffect opening movement of said switch member, separate adjusting meansfor adjusting the relative positions of said bimetal element and saidmembers, the adjusting means for said indicating member comprising meansfor moving the pivot for said indicating member relative to said bimetalelement.

7. In a circuit breaker having a movable switch member and operatingmeans for moving said switch member to open and closed positions,indicating means comprising a pivoted indicating member movable from anormal position to an indicating position to effect an indication, asupport member movably supporting the pivot of said indicating member, atrip member movable to effect opening movement of said switch member, asingle bimetal element normally releasably restraining said indicatingmember and said trip member. said bimetal element being heated by thecurrent of the circuit and when heated in response to overload currentsof predetermined magnitude bending an extent sutiicient to release saidtrip member, said bimetal element when heated in response to overloadcurrents greater than said predetermined magnitude bending a greaterextent to release said trip member to effect opening movement of saidswitch arm, adjusting means for adjusting the relative positions of saidtrip member and said bimetal element, and separate adjusting means foradjusting said support members to thereby adjust the position of thepivot for said indicating member relative to said bimetal element.

8. In a circuit breaker having a switch member and operating means formoving said switch member to open and closed positions, an auxiliarydevice, a plurality of members movable from a normal position to anoperating position, one of said movable members when moved beingoperative to actuate said auxiliary device and the other movable memberwhen moved being operative to effect movement of said switch member toopen position, a single bimetal element normally restraining both ofsaid movable members and operable in response to certain abnormalcircuit conditions to effect movement of said one movable member toactuate said auxiliary device and further operable in response tocertain other abnormal circuit conditions to effect movement of saidother movable member and cause opening movement of said switch member,separate adjusting means for adjusting the relative positions of saidbimetal element and said movable members, and said adjusting means forsaid one movable member comprising means for moving said one movablemember relative to said bimetal element.

9. In a circuit breaker having a switch member and operating means formoving said switch member to open and closed positions, two auxiliarydevices, one of said auxiliary devices being operable to effect anindication and the other of said auxiliary devices being operable toeffect an indication and to cause automatic opening movement of saidswitch member, a single bimetal element operable in response to overloadcurrents, said bimetal element being operable in response to certainoverload currents to effect operation of said one auxiliary device andoperable in response to certain other overload currents to effectoperation of both of said auxiliary devices, and said one auxiliarydevice being resettable by predetermined movement of said operatingmeans without resetting the other of said auxiliary devices.

10. In a circuit breaker having a switch member and operating means formoving said switch member to open and closed positions, two auxiliaryswitches operable to effect an indication, two releasable members, oneof said releasable members when released operating one of said auxiliaryswitches, the other of said releasable members when released operatingthe other of said auxiliary switches and effecting automatic movement ofsaid switch member to open position, a single bimetal element normallyreleasably restraining said releasable members, said bimetal elementbeing operable in response to certain overload currents to release saidone releasable member to cause operation of said one auxiliary switchand said bimetal element being further operable in response to certainother overload currents to release said other releasable member to causeoperation of said other auxiliary switch and opening movement of saidswitch member, said one releasable member being resettable bypredetermined movement of said operating means to effect opening of thecorresponding auxiliary switch without resetting said other releasablemember whereby said indication is maintained until both of saidreleasable members are reset.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,169,586 Leonard Aug. 15, 1939 2,259,097 Anderson Oct. 14,1941 2,416,407 Runke Feb. 25, 1947 2,468,645 Steinmayer Apr. 26, 19492,487,534 Favre Nov. 8, 1949

